1. Technical Field
The invention relates to imaging technology and, particularly, relates to a lens module with focusing function.
2. Description of Related Art
Lens modules commonly employ a focusing/zooming function for adjusting an image plane thereof to produce a high quality image. A typical focusing/zooming lens module includes a lens barrel, a lens group, a lead screw, a transmission nut, a motor, and two stop portions. The lens group is slidably received in the lens barrel. The lead screw is set so that the longitudinal direction thereof is parallel to the optical axis of the lens group. The transmission nut is meshed with the lead screw, and is connected to the lens group. The motor is configured for driving the lead screw to rotate to force the transmission nut to move, with the lens group, along the lead screw to a focused/zoomed position. The two stop portions are configured for delimiting a movable boundary of the transmission nut (the focusing/zooming range of the focusing/zooming lens module).
In such focusing/zooming lens modules, an over-rotation of the lead screw (the lead screw continues rotating until the transmission nut abuts against the stop portion) caused by misoperations of users or control errors of the motor may cause the lead screw to engage with the transmission nut, and then cannot be disengaged. And so, the focusing/zooming lens module loses the focusing/zooming function.
Therefore, it is desirable to provide a lens module with focusing function, which can overcome the abovementioned problem.